Device for grinding saw-bits



2 Sheets-Sheet L..

(11b Model.)

N. w. S PAULDING.

DEVIGE FOR GRINDING SAW BIT$.

No. 351,666. Patented 00t.26, 1886.

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N. WJSPAULDING.

. DEVICE FOR GRINDING SAW BITS. No. 351,666. Patented Oct. 26, 11886.

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UNITED {STATES PATENT OFFICE.

NATHAN \V. SPAULDING, OF SAN FRANCISCO, CALIFORNIA.

DEVICE FoR GRINDING SAW-BITS.

SPECIFICATION forming part of Letters Patent No. 351,666, datedoer-obel- 26, 1886.

Application filed June 18,1885. Serial No. 169,108. (No model.)

T 0 all whom it may concern.- Be it known that 'I, NATHAN W. SPAULDING,

of the city and county of San Francisco, State of California, haveinvented an Improvement in Devices for Grinding Saw-Bits; and I here, bydeclare the following to be a full, clear, and exact description of thesame.

My invention relates to a device for accurately sizing and sharpeningbits which are to be used in saws.

It consists of a series of tables having gages to receive a holder inwhich the bit is inserted, so that the bit may be advanced transverselyacross the edge of a rotating emery-wheel or grinderandthebitsharpened,a concave formed upon its edge and under surface, andthe edges ground to the proper width.

Referring to the accompanying drawings for a more complete explanationof my invention, Figure 1 is a view of my apparatus, showing the mannerof grinding a concave on the edge. Fig. 2 is a plan view showing thedevice for grinding and gaging the edges of the bit. Fig. 3 is a view ofthe holder. Fig. 4. is a view of the holder, showing the notch K.

A is an emery or grinding wheel, mounted upon a shaft or arbor, B, whichis driven at a high rate of speed by a belt passing around a pulley, O.

D is a horizontal table,having its-upper surface and edges accuratelyplaned to serve as a guide and support for the movable standard orsupport E of the bit-holder. The table D has a plate or shank, F,extending downward at right angles from it, and moving in guides G,which are'bolted to a base-plate, H. The plate and guides are slotted orperforated to receive a locking-bolt, which passes through the slot inthe plate and screws into the back guide, so that the plate and thetable D may be adjusted up or down, as may be desired.

The upwardlyextending sides of the standard E have bearings slotted infrom the top to receive thejournal-pins or trunnions j of the bit-holderJ. This bitholder consists of a lower jaw, from which the trunnions orjournal-pins project on each side, and having the front portionflattened to receive the lower and straight part of the bit. The upperjaw is made V-shaped to fit into the groove which is formed on the. backof the bit, and it has a notch, K, made transversely in it, to receivethe transverse baror key which extends across the groove in the back ofthe bit.

Upon the front part of the movable support E is an adj usting-screw, L,which may be fixed at any desired point, so that the front portion ofthe lower'bit-holding jaw will rest upon it, and when this is done theedge of the bit will be brought into such a position that by moving theslide E forward upon its guide and support D the lower front edge willbe moved transversely across the edge of the grindingwheel A, whichrotates at right angles with it. By this construction the bits arealways moved across the face of the grinding-wheel at exactly the sameangle, and they will be concaved with an are which corresponds with theexterior diameter of the grinder.

Upon each side of the standard or guide G a horizontal table, M,projects, and each table has a slotted guide, N, made in it so as tostand parallel with the side of the grinding-wheel.

A gage-block, O, is fitted into each of these v slots, and the side 1?of each of these blocks is "beveled or'inclined, so that when the sideof the bit-holderJis placed againsttheincline and the front corner of itfits against. theshoulder at Qthe side of the bit will be brought incontact with the edge of the grinding-wheel. and any surplus materialupon that side will be taken off. By placing the bitholder against thesimilar gage upon the opposite side, the other edge of the bit will bealso ground. These gage-blocks are adjusted by screws S,

so that when the bit-holder is placed against each of them the sides ofthe bit will be cut away so as to leave exactly the same width upon eachside of a central line. It will be manifest that all these tables andgages may be adjusted to fit larger or smaller grindingwheels, as may bedesired.

Having thus described my invention, what I ICO having bearings for thejournal-pins, and a grinding-wheel revolving in a plane at right angleswith the movement of the standard, substantially as herein described.

3. A bit-holding forceps with journal-pins and supporting-standard, inwhich said pins may rest, and an adjusting screw or gage, upon which thefront forceps may rest, in combination with a revolving grinding-whee],substantially as herein described.

4. A device for gaging and centering sawbits, consisting of horizontaltables extending to a point near the face of a revolving grindingwheel,and having adjustable gages attached to them, in combination with a bit-15 holder fitted to rest against said gages, so as to bring the oppositeedges of the bit alternately in contact with the edge of the revolvinggrinding-disk, substantially as herein described.

In witness whereof I have hereunto set my hand.

SPAULDING.

